Astrophysical Simulation Software for Unix and Windows 95/NT

As a part of
our new Astronomy Lab Manual, I have written some interactive
software exercises that illuminate some of the more abstract notions
of basic astrophysics in a graphical and hands-on manner. These
program are freely available for MS Windows (3.1, 95, NT) and some flavors
of Unix (Solaris, Linux, Mac OS X coming soon). Please email me if you
use or like them. I'd especially like to know if you use them in a
teaching situation. Source code is available upon request.

In the Gravity and Planetary Orbits program, you can drop a
planet into a virtual solar system and observe the resulting orbit
(complete with time, velocity, and acceleration information).
Here's a piece of the display window and the control panel button bar.
The dotted white circular line shows a circular orbit from the
starting position, the red orbit is the one drawn. The user can mark
the orbit with big dots at any time interval (in this example, the blobs
are drawn every 0.1 year).

TOP view SIDE view

And now the real thing... NGC 4038/9!

Cool, huh?This is a simple program designed to graphically portray how disk
galaxies can transform themselves through collisions. The two disks
are set up with up to 3000 test 'particles' in Keplerian orbits around two
centrally-dominated masses -- approximately at the sophistication of the
landmark Toomre and Toomre papers of the 1970's.

The goal of the program is to facilitate curiousity and tinkering, as well as providing an impressive real-time movie of the galactic interactions.

Famous twisted galaxies like M51 and NGC 4038/9 can be nicely
modeled using this program. Matter bridges, tidal tails, and ring
galaxies can all be neatly demonstrated in real time.